Family: Cyperaceae

Origin, Description & Uses
Cyperus papyrus, commonly known as papyrus sedge or paper reed, is a tall aquatic plant native to Africa, especially along the Nile River and in tropical wetlands. It is a striking sedge that can grow 6–15 feet tall, with thick, triangular green stems topped by large, umbrella-like sprays of fine, threadlike rays. Historically, papyrus was famously used in ancient Egypt to make paper, boats, mats, baskets, and other woven goods. Today, it is widely planted as an ornamental in water gardens, ponds, and landscape features due to its dramatic architectural form and ability to thrive in shallow water.

Risks & Threats
Papyrus sedge is naturalized on Kauaʻi, Oʻahu, and Hawaiʻi Island. It reproduces by seed and spreading underground rhizomes, forming dense stands in wetlands, stream margins, and other saturated areas. These thick colonies can crowd out native wetland plants, alter water flow, trap sediment, and reduce habitat quality for native wildlife. Its rapid growth and tolerance of a wide range of wet conditions are traits that are cause for concern. Because it is well adapted to tropical climates and capable of spreading beyond cultivation, this species could detrimentally impact fragile tropical island ecosystems if not carefully managed.

High Risk Traits:

• Environmentally versatile in tropical and subtropical climates
  
• Widely naturalized
  
• An environmental weed that threatens endangered species
  
• Sometimes considered a nuisance, forming floating islands that obstruct navigation and water flow
  
• Other Cyperus species are invasive
  
• Possible toxicity to humans
  
• Tolerates many soil types
  
• Thicket-forming aquatic weed
  
• Seeds dispersed by water, wind and possibly by adhering to mud on vehicles or animals
  
• Spreads vegetatively
  
• May form a persistent seed bank
  
• Able to resprout after repeated cutting

Low Risk Traits:

• Unarmed (no spines, thorns or burrs)
  
• Palatable to grazing animals
  
• Ornamental
  
• Limited seed production may minimized dispersal if confined to water gardens or contained water features